The first lawsuit has been filed against President Donald Trump‘s controversial national emergency declaration. Several Texas landowners and the Frontera Audobon Society say they’ll be adversely affected by construction for the president’s proposed wall on the U.S.-Mexico border.

Filed by consumer watchdog group Public Citizen in the U.S. District Court for the District of Columbia, the 19-page lawsuit is likely the first of many legal challenges to be brought against Trump over his efforts to use the executive branch’s congressionally-gifted national emergency powers in lieu of legislative methods to fund and construct the border wall.

The lawsuit accuses Trump of acting in violation of various federal laws and the U.S. Constitution by issuing an unlawful emergency declaration that “exceeds the limited authority delegated to the president to declare national emergencies and invoke specific statutory powers conferred by Congress to act in such an emergency.”

The filing flatly alleges that Trump declared an emergency to side-step Congress:

Rather than responding to an emergency requiring immediate action, the Declaration seeks to address a long-running disagreement between the President and Congress about whether to build a wall along the southwestern border and Congress’s refusal to appropriate funds for that purpose. However, under our Constitution, built on the principle of separation of powers, a disagreement between the President and Congress about how to spend money does not constitute an emergency authorizing unilateral executive action.